You may just be a bit more on the introverted side of the spectrum and that's normal. There are social expectations that we should "have lots of friends" and that college is a time to meet and hang out with people and do crazy stuff to think back on when we are in our 40s. I think those sentiments were created a few generations back when the cost of college wasn't necessarily a concern. But even you, who managed to do it so far without debt, had to think about the cost as a big factor and it impacted how you attended. Surprise! A bunch of young adults trying to get an education while being stressed about a potentially life-altering amount of debt and an uncertain future aren't really in the best place to be social and have fun. My point is don't blame yourself; the system is kind of fucked right now.

If you get your degree that's great, you'll have access to more doors in life and hopefully that means more free time to devote to things you already know you like and maybe some stuff you've yet to find out you like. If you feel like you want more friends, there are social clubs, discord servers, and meetups in towns/cities you can look into to find folks who are more or less aligned with your interests rather than your education level. There is still a lot about life you've yet to see and I think a not-so-great college experience won't be something you think about even a year after graduation.